Turbine rotor formed of laminated plates with aperture overlap



Nov. 18, 1952 s A. KANE 2,618,462

TURBINE ROTOi? FORMED OF LAMINATED FIQJL.

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1x .1. F w as 37 :54 E; 52V 58 Z INVENTOR.

Soul Allan Kane Patented Nov. 18. 1952 TURBINE ROTOR FORMED OF LAMINATED PLATES WITH APERTURE OVERLAP Saul Allan Kane, Washington, D. 0.

Application December 30, 1948, Serial No. 68,105

3 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This invention relates to turbines with special reference to rotor construction.

It has been common practice in turbine rotor construction to form the rotor as a casting including the central main section and radial blade sections integral with the periphery thereof. High temperature alloys are required and castings involve difliculties including the necessity of elaborate equipment and care to prevent pits, blow holes, inclusions and the like. Moreover, forging is possible only with small and medium sized rotors. With solid unit castings also there is considerable difficulty in forming adequate cooling passageways in the blades; and the root of the blade tends to fracture due to the relatively sharp angle of junction thereof with the base rotor section.

The present invention contemplates overcoming the difiiculties above enumerated by forming the rotor of stacked thin plate laminations of the desired high temperature metals, these laminations being stamp-ed to include the central base section of the rotor and also the radial blade sections with crack preventing junctions therebetween. In addition, openings may readily be stamped in the blades either to reduce blade density or for this purpose and also to provide passage-ways for coolant.

Among the objects of the invention are to provide a turbine rotor with asily formed coolant or weight reducing passage-ways; to provide a rotor with blades resistant to blade defects at the root thereof; and to provide a rotor made of refractory materials utilizing a simplified process of construction.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with th accompanying drawings wherein- Fig. 1 is a perspective view of a sector of the turbine rotor showing blades constructed according to the invention;

Fig. 2 is an elevation partly in section showing the rotor and rotor supports and illustrating lamina overlapping to secure a square U form of passage-way;

Fig. 3 is a section through one of the blades as indicated by line 3--3 of Fig. 1, showing the transverse cavity produced by overlapping openings in the various laminas,-

Fig. 4 is an elevational section through a blade showing laminas overlapped to produce a passageway having a roughly V-shaped contour;

Fig. 5 is a view of an interior stamped plate of the blade assembly showing the blade root construction and the lightening and coolant apertures; and

Fig. 6 is a view of the rotor sid with a section removed to show the lamina overlap at the peripheral duct.

The turbine rotor H], as shown in the drawings, is constructed of a plurality of stacked metal laminas ll each comprising a main body section 12 and a blade section 13, the blade sections extending radially from the periphery of the body section. Since the laminas are stamped from thin plates it is feasible to use refractory alloys which are particularly desirable for gas turbine use. The construction usually desirable for high speed turbine use-requires a circular base section, although this formation may be varied.

In order to insure a strong and permanent connection between blade and body sections and prevent development of defects at the junction area, the lamina is stamped so as to produce a curved edge at the blade section root. More specifically as shown in Figs. 1 and 5 the blade section edges are continued beyond the circumferential outer edge of the body section and reversely curved to the body edge, so that the edge form is entirely curved at the junction region M. By this means development of cracks due to sharp angled junctions, as frequently develop in castings, is avoided.

The mode of lamina assembly in the rotor is indicated in Figs. 2 and 5. A stub shaft 23 is utilized and the laminas stamped to proper form are assembled on this shaft with a key connection to prevent relative rotative motion. The plates are then bound together by end plates 2! and 22 and cross bolts 23 passing through the end plates and laminas. The end plates are fixed on the shaft by any appropriate means as by detents to prevent axial shifting of the rotor unit. While exact juxtaposition of the lamina with blade sections in registry is a usable structure, Fig. I, however, illustrates a curved arrangement so as to produce the desired bucket or pocket effect. This is obtained by a step-by-step overlap by keying the plates to the shaft at an angle to the shaft axis, with proper consideration of the shape of blade desired, such as the crescent sector of Fig. 1. Fig. 3 illustrates the type of cavity obtained by the overlap construction as shown in Fig. 1; with the cavity progressively increasing in width from the edges to the center due to the diminishing rate of overlap approaching the center.

The use of thin stampings not only permits use of refractory alloys but also lends itself to blade density variation and coolant passage construction. For example, as shown in Fig. 5, each blade section may be stamped to obtain a square aperture 30 which, on plate assembly, becomes a transverse cavity 3| in the blade. In this manner the density of the blade is reduced for high speed rotation, and, if desired, coolant use is made possible by utilizing the cavity as a passageway for cooling fluid. To this end, that is, for cooling purposes, it is required that the plate stacking be such as to obtain a continuous cavity across the blade width; and, also, it is necessary that proper inlet and outlet ducts be provided. This may be accomplished by forming radial ducts or grooves 32 and 33 in the two exterior body plates 28, 29 which communicate with the transverse cavity 3| and separate axial bores 34 in the shaft. Communication with the bores is established by radial ducts 35 and 36 which are enclosed by drums 31 and 38 sealed about the shaft at the drum ends, as by rotative slip connections 39. Tubes 40 and 4| form, respectively,

the inlet and outlet connections to the drums 37 K and 38.

Fig. 4 illustrates a variation of the cooling duct of Fig. 2 in that the passageway 50 is formed by making the duct apertures of varying width and distance from the blade section base; so that the duct formation in elevation more nearly approaches the shape of a V instead of a U, as in Fig. 2. Obviously, any other desired shape of the passageway may be obtained by appropriate aperture placement and overlap.

It appears from the above description, there fore, that not only may highly refractory metals be used readily in this turbine rotor construction but also, by using simple stamping operations, the density of the blades may be reduced internally and cavities formed for cooling fluids. Moreover, the life of the blades is extended by this construction through prevention of crack formation at the blade roots.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. In a turbine, a rotor therefor comprising plural juxtaposed plates secured together and formed with body sections and radially projecting blade sections juxtaposed to form a blade body, each blade section having an interior opening therethrough, and the blade section openings registering at least in part, thereby forming a longitudinal coolant passage-way in the blade body, said rotor having axially spaced radial passages meeting said passage-way, and end plates secured to said juxtaposed plates, said end plates having solid radially projecting blade sections covering the ends of said registered openings.

2. In a turbine, a rotor therefor comprising plural juxtaposed plates formed with body sections and radially projecting juxtaposed blade sections, each blade section having an interior opening therethrough, and the blade section openings registering at least in part, whereby a coolant passage-way is formed in the blade body, and end plates for said juxtaposed plates, said end plates being secured together with said juxtaposed plates and having a duct formed therein connecting to a transverse end of the blade passage-way, whereby inlet and outlet connections for coolant may be made.

3. In a turbine, a rotor therefor comprising plural juxtaposed plates formed with body sections and radially projecting juxtaposed blade sections, each blade section having an interior opening therethrough and said openings registering at least in part to form a transverse coolant passage-way, a shaft having axially spaced axial ducts formed therein upon which shaft said plates are attached between said ducts, and inlet conduit connections to one of said shaft ducts and outlet conduit connections to the other of said shaft ducts, and end plates secured to said juxtaposed plates, said end plates being formed with ducts connecting the transverse coolant passageway with the respective shaft ducts.

SAUL ALLAN KANE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 702,461 Nadrowski June 17, 1902 1,455,022 Dake May 15, 1923 1,936,244 Bergstrom Nov. 2-1, 1933 2,187,033 Hubacker a- Jan. 16, 1940 2,354,304 Celio July 25, 1944 FOREIGN PATENTS Number Country Date 125,959 Germany Nov. 26, 1901 141,017 Great Britain 1919 400,534 Great Britain Oct. 26, 1933 736,188 France Sept. 12, 1932 919,016 France Nov. 18, 1946 

